The invention relates to a power cord having a first and a second end, provided with a power cord transformer comprising a core of ferromagnetic material, and a first wire wound around a part of the core as primary coil and a second wire wound around a part of the core as secondary coil, the ends of the first wire extending to the first end of the power cord and the ends of the second wire extending to the second end of the power cord. This type of power cord is particularly used for portable apparatuses used on journeys. Examples are portable telephones, portable computers and shavers.
U.S. Pat. No. 5,539,369 describes a power cord of this type with a power cord transformer having a core which consists of a plurality of separate toroids whose axes are in alignment. The toroids thus form a row. The primary coil of this transformer consists of a wire which is wound around the row of toroids. To this end, the conducting wire constituting this coil is wound a number of times in the axial direction within and outside the row of toroids. The secondary coil consists of a similarly wound wire.
The known power cord has drawbacks in practice. It has been found that an unacceptably high percentage of these cords becomes defective during use by consumers. The method of producing the power cord described in the patent is also very cumbersome. In this method, separate wire pieces are provided and subsequently secured to each other.